观《深入理解C#》有感--- 排序搜索

合集 - 《深入理解C#》读书笔记(8)

1.观《深入理解C#》有感--- 排序搜索2024-07-10

2.观《深入理解C#》---委托和事件的区别2024-07-103.观《深入理解C#》有感---泛型的反射应用2024-07-114.观《深入理解C#》有感---List<T>对于ArrayList的优化提升2024-07-115.观《深入理解C#》有感---泛型类中的静态字段2024-07-116.观《深入理解C#》有感---泛型五种约束2024-07-107.观《深入理解C#》有感---Nullable装箱和拆箱2024-07-168.观《深入理解C#》有感---泛型可变性的缺乏2024-07-12

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关于在无序列表中，找到所需数据的五种写法

    class Program
    {
        class Product
        {
            public string name;
            public int price;

            public override string ToString()
            {
                return name;
            }
        }

        static void Main(string[] args)
        {
            List<Product> products = new List<Product>()
            {
                new Product(){name = "A", price = 5},
                new Product(){name = "B", price = 10},
                new Product(){name = "C", price = 15},
            };

            // 例子1
            foreach(var product in products)
            {
                if(product.price >= 10)
                {
                    Console.WriteLine(product);
                }
            }

            // 例子2
            Predicate<Product> predicate = delegate (Product p) { return p.price >= 10; };
            List<Product> matches = products.FindAll(predicate);
            Action<Product> print = Console.WriteLine;
            matches.ForEach(print);

            // 例子3
            products.FindAll((p) => p.price >= 10).ForEach(Console.WriteLine);
        
            // 例子4
            foreach(Product product in products.Where(p => p.price >= 10))
            {
                Console.WriteLine(product);
            }

            // 例子5 LINQ语法
            var filiered = from Product p in products
                           where p.price >= 10
                           select p;
            foreach(Product product in filiered)
            {
                Console.WriteLine(product);
            }
        }
    }